"Prop. Requirement Met" bug?

[bewing]

Win V7 64bit, running 32bit steam version of KSP v1.0.5.1028

 

I did this once and saw a problem with my Wheesley engine, so I duplicated the flight and got the same result.

OK, I'm flying toward the north ice cap, heading 30 degrees from KSC, at 5000 meters altitude, 240m/s. I'm 32:29 into the flight, and my Prop. Requirment Met is reading 97% and everything is good. One second later, my Prop Requirement Met drops in half to about 45%, my thrust falls in half, and my plane starts to fall out of the sky. The Prop Requirement Met value keeps falling and falling even as I scrub altitude, because I cannot maintain any airspeed. Eventually the plane ends up on the ground in some adjustable number of pieces.  If I fly it down, then a couple minutes later, at 0 altitude and about 130m/s, the Prop Requirement Met value is down to about 18% as I recall. WTF? I have a screenshot at 32:33, but the system won't let me upload it.

 

Edit: After a little more testing, the bug is in the fuel flow system from this particular aircraft design. The program is effectively giving me an infinite amount of fuel -- it "knows" that there are still 800 units of fuel left in the two front tanks, and it is somehow still drawing fuel at a max rate of .04/s (which is not enough to keep my plane airborne), but it is not subtracting any of that fuel flow from those tanks. So they are sitting there stuck at 400 units each. My plane partially runs out of power when the back 4 tanks get depleted of liquid fuel.

I admit the design is funky. It's built to take a pilot and scientist halfway around the planet, taking lots of science samples along the way, then climb to 19000 meters 3 times with enough control that I can still land it one last time afterward. The fuselage of my plane (from front to back) is: small circular intake, MK1 command pod, MK1 liquid fuel fuselage, MK1 inline cockpit, MK1 liquid fuel fuselage, Science Jr., then 4 FL-T200 tanks, then a Wheesley, with a Thud strapped below the Wheesley. I suspect something about that order is blocking the fuel.

 

Edited December 1, 2015 by bewing
more testing info

[Padishar]

This is a known bug.  Hopefully it will get fixed for the next update.

[r_loewe]

i hope 1.0.6 is out soon. this is very annoying because i am trying to do the grand tour of ksp with mining but, my nuclear engines suddenly drop from 100 to 3 percent please help anybody

[FullMetalMachinist]

59 minutes ago, r_loewe said:

i hope 1.0.6 is out soon. this is very annoying because i am trying to do the grand tour of ksp with mining but, my nuclear engines suddenly drop from 100 to 3 percent please help anybody

Welcome to the forums! 

I hope you haven't been deliberately mislead, but 1.0.6 is not, and never has been, a thing that is going to happen. 

However 1.1 is due to come very soon, but I haven't heard if this specific bug has been squashed. 

As for your specific problem, could you post a screenshot of your craft? You'll need to upload it to an image hosting site (imgur.com works great) and then post the link here. 

[r_loewe]

still is not fixed GRRRRRRRRRRRRRRRRRRRRRRR!!!

Edited June 17, 2016 by r_loewe

[bewing]

On 6/17/2016 at 9:50 AM, r_loewe said:

still is not fixed GRRRRRRRRRRRRRRRRRRRRRRR!!!

Well, it's sort-of-fixed.  The SciJr now does fuel crossfeeding correctly AFAIK -- I've been testing that one repeatedly. (Haven't tested it yet in 1.1.3 yet, though.)

Not sure which part is causing the problem with your spaceplane (there are several possibilities). But yes during 1.1 beta testing I discussed this issue with the Squad guys, and they were saying that they are very aware of it, but the whole fuel flow system is going to need to be revamped in order to solve it. So a full solution may be put off until 1.2.0.